1. Field of the Invention
The present invention relates to a mouthpiece unit of a diving respirator, and more particularly relates to a mouthpiece unit having a valve for opening and closing an aperture of a mouthpiece side of a mouthpiece unit body.
2. Description of the Prior Art
In a conventional mouthpiece unit of a diving respirator, a manually operatable valve for closing a mouthpiece is provided in order to prevent water from invading into the mouthpiece unit through the mouthpiece, when the mouthpiece is off the mouth of the diver in the water.
As stated above, in the conventional mouthpiece unit of the diving respirator, the valve of the mouthpiece unit is operated manually, so that the diver must be skilled in the operation of such valve and such valve is unsuitable for the general diver.
Accordingly, a new mouthpiece unit has been proposed. In such new mouthpiece unit, a valve is mounted on a mouthpiece unit body for opening and closing an aperture in the mouthpiece unit body and an operation lever for operating the valve is projected from the mouthpiece unit body so that the operation lever can be operated against a spring force by the jaw of a diver, when a mouthpiece of the mouthpiece unit is held in the diver's mouth.
However, in such new mouthpiece unit, a considerable force is required to operate the operation lever, so that the jaw of the diver get tired.